Power transmission



Dec. 31, 1946. H. F. VICKERS 7,

' POWER TRANSMISSION Filed May 2, 1938 12 Sheets-Sheet 1 INVENTOR HARRYF. VlCKERS ATTORNEYS Dec. 31, 1946.

H. F. VICKERS POWER TRANSMISSION l2 Sheets-Shes 2 Filed May 2 1938mwam'roa HARRY F. \MCKERS I, ATTORNEYS Dec. 31, 1946. H. F. VICKERSPOWER TRANSMISSION Filed May 2, 1938 12 Sheets-Sheet 3 5 R m //Q m S RAW m M [Y W -2 uH A I Q- 0076 7 J r M W 8. B J 2. ll 0 l o l 60 o... tr.8N n- "HI 5 II- 0 I own 6... TOM Mr. ON 1 0 Mn. 0 l \WQ- 8.0 Q. L. O-MHI. 0' a.

Dec. 31, 1946. H. F.'VICKERS POWER TRANSMISSION Filed May 2, 1958 12Sheets-Sheet 4 SIG . v 12mm" SIO FIG. 3

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POWER TRANSMISS ION Filed May 2, 1938 l2 Sheets-Sheet 5 INVENTOR HARRYF- VECKERS ATH'URNEYS Dec. 31, 1946.

H. F. VICKERS POWER TRANSMISS ION I2 Sheets-Sheet 7 Filed May 2, 1958 i5 JU INVENTOR HARRY F. VICKERS Dec. 31, 1946.

H. F. VICKERS POWER TRANSMISSION Filed May 2, 1938 12 Sheets-Sheet 8 mum, INVENTOR HARRY FT V\C.KERS

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POWER TRANSMI S S ION Filed May 2, 1958 12 Sheets-Sheet l2 1 ea 1 l l IZ J I I KP -c l n 455 Q 45s 4 0 Q INVENTOR v Q HARRY F \IICKERS 6 I BY jz 49- um, 4% w ATTQRNEYS Patented Dec 31, 1m

Harry F. Vickers, Detroit, Mich., assignor to Victor: Incorporated,Detroit, Micln, a corporation of Michigan Application May 2, 193a,Serial No. 205,461

v 29 Claims. (01. oo-ss) 1 This invention relates to power transmissionsand more particularly to those of the fluid type wherein a powertransmitting fluid. such as oil, and hereinafter referred to as such, isutilized for the transmission of power between one or ,more pumps andone or more fluid motors.

,This invention is particularly concerned with a power transmissionprovided with a follow-up control mechanism for driving any suitableload device, such as a ships rudder, or other device which it is desiredto move at will to any desired position.

It is an object of the invention to provide a power transmission systemincorporating improved follow-up control mechanism making use of a pilotcontrol pump and a pilot response pump driven by the primary controllingmember and by the output member, respectively, and so connected to themain transmission as to cause accurate follow-up motion of the drivenmember in response to actuation of the primary controlling member.

It is a further object to provide a synchronizing device for preventingaccumulative errors due to leakage, slip, etc. in such a hydraulicfollow-up control system.

It is also an object to provide improved means for protecting the primemover and the trans- -mission against excessive overloads imposed by thedriven device, either in the resisting direction or in the overrunningdirection.-

It is also an object to provide a transmission system of the characterdescribed, wherein auxiliary drive means are provided independently ofthe prime mover, and wherein certain of the protective control means maybe utilized while such auxiliary drive is in operation.

A further object is to provide automatic means of an improved form forrendering the auxiliary drive effective upon failure of the prime mover.

Another object, is to provide the transmission system constructed inunitary sections permit- I ting of ready assembly and disassembly andincorporating means for simultaneously coupling a plurality ofinterconnecting conduits and mechanical driving members concurrentlywith the invention will be apparent from the following description,reference being had to the accompanying drawings wherein a preferredform of the present invention is clearly shown.

In the drawings:

Figure 1 is a diagrammatic view of the hydraulic circuits incorporatedin a preferred embodiment of the present invention.

Figure 2 is a front view of the assembled mechanism.

Figure 3 is a side view of the assembled mechanism.

Figure 4 is a section on line 4-4 of Figure 2.

Figure 5 is a cross-section on line 5-5 of Figure 3.

Figure 6 is a cross-section on line 8-8 of Figure Figure 7 is afragmentary, sectional view corresponding to a portion of Figure 2,parts of the mechanism being broken away for clearness of illustration.

Figure 8 is a fragmentary sectional view of a portion of the mechanismcorresponding to Figure 2, certain of the parts being broken away forcleamess.

Figure 9 is a cross section of line 8-9 of Figure8.

Figure 10 is a cross-sectional view of the upper end of the controlstandard, viewed in the same direction as Figure 2, and being taken online lii--'l0 of Fi ure 12.

Figure 11 is a fragmentary sectional view on line li-li of Figure 12.

Figure 12 is a fragmentary sectional view on line i2--i2 of Figure 10.

Figure 13 is a fragmentary sectional view on line 13-" of Figure 12.

Figure 14 is a fragmentary sectional view taken on line il-H of Figure16.

Figure 15 is a fragmentary sectional view on line l5'l5 of Figure 16.

Figure 16 is a fragmentary sectional view. viewed from the top in Figure2, showing the mechanism inside the main reservoir casing.

Figure 17 is a fragmentary sectional view through the fluid motor andcontrol block, taken on line I'I-i'l of Figure 15.

Figure 18 is a fragmentary sectional view of a torque responsive valve,being taken on line l8--l8 of Figure 15.

Figure 19 is a fragmentary sectional view of the variable displacementpump mechanism, being taken on line l8i8 of Figure 16.

Figure 20 is a detailed sectional view of a con- 3 stant horsepowercontrol valve, being taken on line 2828 of Figure 14.

Figure 21 is a fragmentary cross-sectional view of the pump controllingfluid motor, being taken on line 2l2i of Figure 16.

Figure 22 is a detailed view, partly in section, of a limit stopmechanism, looking in the direction of line 22-22 of Figure 16.

Figure 23 is a cross-section on line 23-23 of Figure 22.

Figure 24 is a fragmentary sectional view of an automatic clutchcontrolling mechanism, taken on line 24-24 of Figure 12.

Figure 25 is a fragmentary sectional view on line 2525 of Figure 24.

Figure 26 is a fragmentary sectional view taken on line 2626 of Figure'7.

Figure 27 is a fragmentary cross-sectional view on line 2'i--2i ofFigure 12.

Figure 28 is a developed view of the torque responsive mechanism shownin Figure 7.

Figure 29 is a fragmentary sectional view taken on line 29-29 of Figure30 showing the construction of a synchronizing valve.

Figure 30 is an end view .of a synchronizing valve shown in section inFigure 29.

Referring to the drawings, the apparatus is illustrated as a unitaryassembly built up of several sections or sub-assemblies which arereadily separable for service and repair. These sections when assembledtogether provide a complete casing for all the internal parts. As shownin Figures 2 and 3 there is provided a main tank unit A carrying a primemover, pump, hydraulic motor and valve block unit, an auxiliary tank andconnector unit B, a horizontal extension unit C,

a vertical extension unit D and a control head E.

The mechanism comprises generally a prime mover, such as an electricmotor indicated at l which is adapted to drive a variable displacementpump l2, connected by main circuit conduits l4 and 16 to afixeddisplacement rotary fluid motor I8, these elements constituting avariable speed power-operated driving means. The output shaft 20 of themotor i8 drives through 'the medium of gears 22--24, shaft 23, and worm25 a load device indicated diagrammatically at 26. The latter mayrepresent, for example, the rack segment of a rudder stock, or othermember, the position of which it is desired to control at will.

The mechanism for controlling the operation of the transmissioncomprises a novel follow-up control system which operates on thevariable stroke pump I2 through a piston and cylinder fluid motor 28connected by control circuit lines 30 and 32 with a primary control pump34 and a response pump 36. The pump 34 is adapted to be driven by handwheels 38,'which form the primary controlling member of the device, thatis to say, they constitute the means whereby selective ,control effortsare put into the mechanism at will. The response pump 36 is con-' nectedto the load device by means of gearing and-shafting connections. Thecontrol conduits 3|] and 32 connect the pumps 34 and 36 in a parallelcircuit with the control motor 28.

Also cooperating with the control motor-28 is a horse-power limitingcontrol system comprising a constant horsepower valve block 46 connectedto opposite ends of the motor 28 by conduits 42 and 44, and adapted totake over control of the motor 28 whenever a predetermined horsepowerload is exceeded. This mechanism operates in combined response to bothpressure in the main stop valves and 52. The pressure responsiveanti-kick valve 46 is adapted to control the main circuit in such amanner as to prevent the motor I8 from imposing sudden excessivepressure loads on the pump l2 when any external force applied to theload device tends to cause the motor l8 to run backward. This valve alsoacts to prevent overrunning of the load device by blocking the returnconduit from the motor l8 to the pump l2 whenever the load device 26tends to overrun.

The torque responsive valve 48 is utilized only during direct drive ofthe load device 26 from the hand wheels 38, at which time the motor l0and pump 12 are out of operation. The valve 48 is for the purpose ofpermitting the motor l8 to pump fluid idly from one side to the otherthereof so long as, during this direct manual drive of the load, neitherexcessive resistance is encountered at the load device 26 nor does theload device tend to overrun.

Thelimit stop valves-50 and 52 are for the purpose of blocking thereturn of fluid from the motor l8 when the load device 26 has been moveda predetermined distance in either direction.

' Cooperating with the hand wheels 38 there is provided an automaticclutching mechanism indicated at 54 for the purpose of selectivelyconnecting the hand wheels 38 to the direct drive mechanism when theprime mover I8 is out of operation, and at the same time bypassing theprimary control pump 34 to permit the latter to bypass fluid idly.

Also cooperating with the hand wheels 38 is a synchronizing valve 53 thepurpose of which is to limit the degree of error possible in therelative angular positions of the hand wheels 38 and the load device 26.p

The mechanisms above described ar incorporated in a unitary sectionalcasing assembly which is adapted to provide a reservoir for oil as wellas to enclose the entire mechanism and provide structural supporttherefor. This casing assembly is arranged in sections and specialprovision is made for connecting the various conduits and mechanicaldriving connections at the joint between sections in an improved andsimplifled manner. The reservoir arrangements are preferably such thatsafe operation is permitted and leakage of oil or entrance of air areprevented, even though the main reservoir should become broken oremptied of oil, thus insuring that the protective mechanismsincorporated in the assembly, may be maintained effective during v handdrive under such conditions.

Referring now to Figures 2 and 3, the pump l2 and motor l8 together withtheir associated control and safety mechanisms are mounted in a mainreservoir casing 56. The motor I0 is secured to one side wall of thecasing 56, 'while the output shaft 23 projects latterly from anotherside wall of'the casing 56. Secured to the casing 56 at the sidethereof, adjacent to, shaft 23, is a lat terly extending casing member58 which contains a'plurality of conduits and a driving shaft (see Fig.4). The casing member 58 is secured means. not shown.

if 8v amass:

to the casing 88 at a flange connection-88, suitable bolts or othersecuring means. not shown, being provided for removabiysecuring themembers 88 and 88 together. The member 88 has an upwardly facingflangeportion 82 to which a vertical casing extension 88 is secured by boltsor other The casing 88 also contains a plurality of conduits and ashaft. Mounted at the top end of the casing section 88 is a controlhead'assembly 88 secured to the section 88 at the flange 88.

The casing section 88 contains suitable bevel gearing for connecting theshaft sections together and also contains the response pump*88. Thecontrol head 88 "contains the primary control pump 88 together with theclutch controlling mechanism 88 and the necessary gearing to establishconnection with the shaft contained in the housing section 88.

The variable displacement pump I2 as illustrated in Figure 19 is of thetype comprising a swinging yoke I8 pivoted on trunnions '12 which alsoform the fluid inlet and outlet connections for the pump I2. The pumpconstruction chosen for illustration is generally similar to that shownin patent to Hans Thoma, No. 1,931,969, and per se forms no part of thepresent invention. Since the operation of these pumps'is well known inthe art, it is sufllcient to state that the quantity and direction offluid flow through the pump may be selectively varied as desired byswinging the yoke 18 to any suitable position. With the yoke in theposition parallel to the pump axis as shown in the drawings, that is, inneutral position, no' fluid is pumped. If the yoke be tilted away fromneutral on one side, the fluid flow will vary in proportion to thedistance which the yoke is moved and will be in a given directionthrough the pump. If the yoke is tilted on the other side of neutral.the flow is in the opposite direction and of course proportional to thedistance away from neutral to which the yoke is swung. The main part ofthe pump comprises a member 18 which is secured to a flange member 18,the latter being removably secured in an opening inthe front wall of thecasing member 56 and forming also a support for the motor I8. v

The shaft 18 of the pump carries a gear 18 which meshes with a gear 88adapted to drive an auxiliary pump 82 which is also secured to theflange member 18. The pump 82 may be of any suitable fixed displacementtype, such as the well known gear pump, and is for the purpose offorming an auxiliary supply of pressure fluid for operating certain ofthe control mechanisms. The pumps I2 and 82 are continuously driven bythe motor I8 at a constant speed whenever the device is used in itsnormal power driven method of operation.

Referring now to Figures 14, 16 and 21; the pump yoke is connected tothe piston 88 of the control motor 28 by a lever 86 pivoted at '88 to apair of links 88 in turn pivoted at 82 on a bracket 98 formed on thehousing of the motor 28.

The opposite end of the lever 88 is pivoted at 86 to a link 88 having aturnbuckle adjustment I88 and having its opposite end pivoted at. I82 tothe yoke 18. A suitable sliding brace rod I88 is secured to therighthand portion of the link 98 and slidably engaged with the. lefthandportion thereof to provide additional columnar stiffness to the link 88adjacent to the turnbuckle section I88.

The piston 88 of the motor 28 is slidably mounted in a cylinder I88 andhas stems I88 and .6, lllproiectingthroughthe'end caps II2 and H8 whichclue the opposite ends of the cylinder I88. The I88 is pivotallyconnected to the lever 88 at 8, while the'stem II8 has a reduced nortionII8 on which spring abutments I28 and I22 are slidably mounted. Acentering spring I28 is positioned between the spring abutments, whilethe latter are encloud in a housing member I28 secured to. the cap II8.The arrangement is such that the spring I28 constantly tends to bringthe piston 88 to its central position illustrated regardless of whetherthe latter be moved to the right or left thereof. Connections I28 andI88 are formed in the end caps H2 and H8 whereby the control conduits 82and 88 are connected tothe opposite ends of cylinder. I88.

Secured on a bracket I82 mounted on the pump housing member 12 is theconstant horsepower valve block 88. This block contains two identicalFigure 28 by a spring I88. Annular ports I88 and I82 are formed in thebore I36 and are cut off from communication with each other when thespool I88 lies in its lefthand position illustrated. The ports I88 andI82 are connected to the conduits 82 and 88 which communicaterespectively with opposite ends of the cylinder I88. Whenever the spoolI88 is moved 'to the right, communication is established by the portsI88 and I82,-..thus bypassing'opposite ends of the cylinder I88 andpermitting the centering spring I28 to move the piston 88' towardneutral position so long as this bypass path is open. Abutting the spoolI88 on its left hand end is a small piston I85, subject to pressure inone of the main circuit conduits I8 or l8, which pressure is resisted bythe spring I88. The degree of compression of spring I88 is variedautomatically in accordance with the position of the yoke 18 by means ofa plunger I88 slidably mounted in the bore I36 and abutting the righthand end of the spring I88.. 4 suitable stop pin I88 prevents theplunger I88 from moving entirely out of the bore I88. A roller I88carried by the plunger I88 is adapted to contact one of two cams I58 andI52 carried by a bracket I58 secured to the yoke I8 (see Figure 16). Thecams I58 and I52 are so shaped that the adjustment of spring I38 isvaried in the correct manner to provide for opening of the bypassI88-I82 whenever the product of pressure in the main circuit anddisplacement of the yoke I8 away from neutral equals a predeterminedvalue. Thus, as the yoke 18 approaches neutral pwition,

the plunger I88 is moved inwardly to the farthest parture from a truehyperbolic relation being preferably introduced to compensate forvariations in transmission efficiency.

Referring now to Figures 7 and 15 through 18, the fluid motor I8 is ofgenerally similar construction to the pump I2 except that a fixed angleyoke member I88 is provided in place of the aerases yoke 18. 831a motorparts together th certain of the protective valve :11

are all mounted in a unitary block E88 which is formed ina transversebore I12 in the block I88 and has an additional pair of ports I14 andI18 spaced from the ports I88 and I18. The port I14 communicates withthe discharge side of a check valve I18 open to free flow from the boreI84, while the port I18 connects to the discharge side of a check valveI88 opening to free flow from the bore I88. Within the bore I12 ispositioned a spool I82 having a central land I84 normally closing theports I88 and I18. At its two ends the spool I82 is provided with pistonheads I 88 and I88 which are subject to pressure in the conduit I4 andI8 respectively. For this purpose, a passage I98 communicates betweenthe bore I88 and the lefthand end of the bore I 12 which is enclosed ina cap member I92. A passage I94 formed in block I88 communicates with agroove I98 formed in a Plate I98 which forms the supporting means forblock I58 and forms also the wall of the reservoir casing 58. The righthand end of the bore I12 is thus placed in communication with the boreI84. A centering spring I98 together with spring abutments 288 and 282normally maintains the valve spool I82 in a central position, butpermits the latter to move to the right when the conduit I8 is thepressure conduit,

and to move to the left when the conduit I4 is the pressure conduit.

The port I18 and a port 284 in line with the port I14 providecommunication to the torque responsive anti-kick valve 48 which is shownin section in Figure 18. The port I18 communicates with a port 288,while the port 284 communicates with a port 288 in the body member 2I8of the valve 48. The latter also has three additional ports 2I2. 2, and2I8 which are normally closed by the spool 2l8 when the latter is in itscentral position illustrated. The spool 2" is normally biased to centralposition by a centering spring 228 and abutment washers 222 and 224 andis adapted to be moved to the right or left when torque is applied inone direction or the other to drive the load device 28 directly from thehand wheels 38. The mechanism for accomplishing this movement will belater described.

Suitable lockout plungers 228 are adapted to engage a groove 228whenever fluid pressure is admitted to the end faces of pistons 298. Thelatter are normally spring .biased outwardly to the position shown inFigure 18. The ports 2I2 and 2I8 communicate by bores 232 and 284 withthe entrance side of a check valve 288 as shown in Figure 1, the outletside of this check valve v 8 block 284 is provided for limiting leftwardmovement of the valve spools 248 and 248. Suitable leakage collectinggrooves 288 and 288 are provided adjacent the projecting stem ends ofthe valve spools and are connected by a e 288.

The groove 288 communicates by a passage 282' formedin the valve spool248 with the space at the right hand end of the spool which later opensto the righthand face of the plate I88.

A check valve 284 connects the ports 242 and 244 of valve 82 for freeflow from the port 242 to the port 244. when the valve 82 is closed. Asimilar check valve not shown in Figure 17 but indicatedat 288 in Figure1 provides for free" flow from port 288 to port 248 when the valve 58 isclosed. The port 248 communicates by a bore 288 and passage 218 with oneside of the motor I8, while a corresponding passage not shown in Figure1'1 but indicated at 212 in Figure 1 connects the port. 244 with theother side of the motor I8. I

The valve block I88 also contains various relief, check, andreplenishing valves shown in Figure 1 and not illustratedin detail inthe sectional views of the valve block I88, these valves being describedin connection with their cooperating circuit portions hereafter.

The mechanism for operating the limit stop valve 88 and 82 isillustrated in Figures 15, 22 and 23. This may comprise a gear 214meshing with a pinion 218 on the output shaft 23 of the unit. The gear214 is secured to a shaft 288, having a worm 282 which meshes with aworm wheel 284. The shaft 288 and the worm wheel 284 are pivoted on abracket 288 secured to the block I58 (see Figure 15). The worm wheel 284carries adjustably mounted thereon a pair of cams 288 and 298 which aresecured by bolts 292 slidable in a circular T slot 294. The cams 288 and298 are adapted to co-act with rollers 298 and 298 which are carried bylevers 888 and 382 respectively. The levers 888 and 882 are pivoted on astationary shaft 384 secured in the bracket 288. Each of the levers 988and 382 is provided with a stop lug 988' normally abutting the bracket288 and with an operating finger 888 adapted to abut thecorresponding'stem 288 or 282-of the valves 88 and 82 respectively. Thegear ratio from the shaft 218 to the worm wheel 284 is suchthat thedesired number of revolutions of the shaft 28 are accomplished in movingthe wheel 284 from the position with cam 288 be-,

neath the roller 298 to the position with cam 298 beneath the roller298. This distance is subject to adjustment at will by adjusting theangular positions of the cams 288'and 288.

The mechanism for actuating the torque responsive anti-kick valve 48 isillustrated at Figures 7 and 28. The stem 8I8 of the spool 2I8hasrotatably mounted thereon a pair of cam sleeves 9I2 and 8 which. arenon-rotatably tongued together at'8l8. Surrounding the cam sleeves M2and M4 is a mating ,cam sleeve 3I8 upon which a gear 828 is keyed. Thegear 328 meshes with a pinion 82I meshing with the gear 24 as shown inFigure 1. The cam sleeve 3I2 is provided with a cam face at 822 engaginga corresponding face on the left end of sleeve 8| 8, while thecam'sleeve 8 is provided with a cam face at 824 engaging with acorresponding cam face on the right hand end of the sleeve 3I8. Thesecam surfaces are of helical form, such that upon relative rotary motionbetween the two cams 8I2 and I on the one hand and the cam sleeve ill onthe other hand. that an axial movement will be imparted to the sleeves3l2 and 314 to the left or right in Figure '1, depending on in whichdirection the relative rotary movement takes place. Preferably thisaxial movement imparted to the stem 318 takes place within a few degreesrotation of the sleeves 312 and 3 relative to the sleeve H8. The sleeves3i2 and 3 are non-rotatably but slidably connected with a member 328 bymeans of a tongue-connection at 328. The member 328 is in turn coupledto a shaft 338 by a tongue connection at 332 to form an Oldhamsconnection. A stop plug 333 is secured to the shaft 338 to retain themember 328 in engagement with shaft 338.

The shaft 338 is connected to the hand wheels 38. as will later bedescribed, and forms an auxiliary direct drive for the load device 28through the torque responsive cam mechanism just described and throughthe gear 328 and pinion 32l.

' The shaft 338 is lournaled in the casing section 58 on bearings 334and 338. A bevel gear 338 is mounted on the shaft 338 and meshes with av bevel gear 348 (see Figure 26) journaled in the top part casingsection 58. The shaft 338 also has keyed thereto a spur gear 344 meshingwith a spur gear 348 keyed to the driving shaft 348 of the response pump36. Ashaft 342, see Figure 8', is floatingly mounted by means of splinesin a sleeve 352 at its upper end and is adapted to enter the hub 358 ofthe bevel gear 348 when the casing section 84 is attached to section 58.

The hub 358 is journaled on anti-friction bear-.

ings 354 mounted in a cage 358 removably secured in the casing section58. The sleeve 352 is mounted on antifriction bearings 358 secured inthe upper end of the casing section 84. An oil seal 360 is mountedadjacent the lower end of the shaft 342' in theverticalcasiriglsection64.

The sleeve member 352 carries a hub 362 (see Figure 9) having atransversebore 364 in which is mounted a spring'366 normally urging apair of balls 368 outwardly. The latter normally repose in holes 318formed in a cup-like member 312 co-axial with the hub 362 andsurrounding the same. The member 312 has 'an upwardy extending shaft 314journaled in a. bearing cup 318 slidably retained in the control headhousing 88 (see Figure 10). The halls 368 and associated mechanism areadapted to form a yielding clutch between the shafts 342 and 314, thuslimiting the torque which may be transmitted therebetween. A brake band315 encircles the cup 312 and may be tightened by a handwheel 311 inorder to lock the handwheels against idle movement when the unit is outof operation.

The shaft 314 carries a bevel gear 318 which meshes with a bevel gear388 keyed on a transverse shaft 382 journaled on anti-friction bearingsin the housing 66. A spur gear 384 is also keyed to the shaft 382 andmeshes with a pinion 386 rotatably journaled on a shaft 388. The latteris journaled in'the housing 66 and carries the hand wheels 38 atitsopposite ends, suitable oil seals 398 being provided at the hubs ofthe wheels The intermediate section of the shaft 388 is splined to carryslidably but non-rotatably a clutch collar 392 having Jaws 394 meshingwith corresponding clutch jaws 336 formed integrally with the hub of thepinion 386. The shaft 388 also has keyed thereto a, spur gear 398 whichmeshes with a pinion 488 (see Figure 12) keyed to the shaft of theprimary control pump 34. The clutch collar 392 is adapted to be shiftedby a shifter fork 482 pivoted at 484 on the clutch m (see Figures 10, 12and 27) adapted to abut a bypass valve for the primary control pump 34.This valve is illustrated in Figure 27 from which it will be seen thatthe spool 4| 4 in its springurged position to the left openscommunication between the pair of ports 4 l 6 and 8 which connect to thetwo sides of the pump 34. When the spool H4. is moved to the right bythe arm 2, this bypass is closed. Viewed in Figure 10, the bypass valveis opened'when the arm 2 moves to the left, while it is closed when thearm 2 moves to the right.

For actuating the shifter 482, the clutch con-' trol block 54 contains aplunger 428 (see Figure 24) having a cam surface 422 adapted tocooperate with the roller 488. The plunger 428 is controlled by a piston424 sliding in a cylinder 428 and spring biased upwardly in Figure 24 bya spring 428.

The block 54 also contains a combined relief valveand bypass valve forthe cylinder 426, this valve being illustrated in Figure 25. A port 438communicates with a conduit 43f (see Figure 1) leading from theauxiliary pump 82 and also communicates with the righthand end of thebore 432 through a conduit 434. An intermediate port 438 communicateswith the cylinder 426 while a second intermediate port 438 communicateswith the interior of the casing 66 through a pipe 438. The spool 448 isbiased to the right by a spring 442 adjustable by means of a screw 444and is urged to the left by the pressure from the auxiliary pump 82exerted in the righthand end of the bore 432. The spool 448, when apredetermined pressurein the conduit 43l-is exceeded, moves to the leftto permit "pressure 'oil'from the conduit 434 to relieve to the interiorof the housing through the port 438. When the valve 448 is in itsrighthand position when there is no pressure in passage 434,communication is established between port 436 and port 438 thus ventingthe clutch cylinder 426. As soon as pressure is established in theconduit 434 and the valve moves slightly to the left, this communicationis cut out and port 438 is connected to port 438 thus admittingauxiliary pressure 011 to the cylinder 426. The parts are shown inFigures 24 and 25 in the latter position.

The synchronizing valve mechanism 53 comprises a double three-way valve445 (Figures 29 and 30) having ports 441 connected to the followupcontrol conduits 38 and 32. The valve 445 is constructed to selectivelyconnect one of the ports 441 with a replenishing oil port 449 and theother to the casing interior or vice versa. The ports 449 are suppliedwith oil from auxiliary pump 82 through a port 5| 8 which connects tothe conduit 434 in valve block 54. The valve 445 is normally springcentered by the spring 45f and spring abutments 453 and it may be movedto the leftor right by a lever 455 pivoted at 451 on the valve block 53.The lever 455 carries a pin 459 which rides in a groove 46l (Figure 10)formed in a sleeve 463 freely rotatable on shaft 382. The sleeve 483 isnon-rotatably but slidably connected to a pinion 485 by pins 481. Pinion485 meshes with gear 388 on shaft 388 so that sleeve 463 is thus causedto rotate with hand wheels 38 but is permitted a certain amount of axialprovided with a groove 488 having a helical porand nut diflerentialmechanism connecting the shaft 882 which moves with the load device, thepinion 488 which moves with the hand wheels, and the lever 485 whichcontrols the valve 445.

The various units are connected together hydraulically as illustrated inthe circuit"diagram of Figure 1. Besides the main circuits-I4 and I8connecting the pump I2 with -the motor I8 and passing throughthefprotective valves 48, 48, 88, and 82, there is the followup controlcircuit comprising thel.conduits"88'- and'82 which connect primarycontrol pump 84, the response pump 86,

- and the contr'ol'fluid motor 28 in a parallel cir- 1 cuit. Also inparallel with this circuit through the conduits-42. and 44 are theconstant horsepower valves I84 and I84 in the block 48. The

jump 82 has. a suction conduit 448 through which oil is withdrawn fromthe reservoir 88 and the delivery conduit 48I which terminates in theclutch control block 54 as previously described. The conduit 48I hasbranches 448 and 458 connecting to the lookout pistons =288 whereby thelatter are projected inwardls whenever pressure exists in the conduit48L The conduit 48I has also a two-arm branch '452 which communicates bycheck valves 454 and 458 with the follow up control conduits 88 and 82respectively. Other branches 488 and 488 contain check valves 482 and484 communicating with the main line conduits I4 and I8 respectively.Suitable pressure relief valves for the main pircuit are provided on thepump side of the protective valves at 488 and 488 and on the motor sidethereof at 418 and 412.

Gravity replenishing valves are also provided for the motor end of themain circuit at 414 and 418 which admit fluid under gravity head from aconduit 418 communicating with an auxiliary reservoir 418 formed by thecasing section 84.

A pressure equalizing conduit 488 communicates between the upper end ofthe reservoir 88 and the interior of the control head housing 88. Therelief valves for the follow-up control circuit lines 88 and 82 areprovided adjacent the response pumps 88 at 484 and 482.

Referring to Figures 4 and '1 it will be seen that the housing section58 is attachable to and removable from the housing section 88 by the 12The sleeves 488 provide a fluid-tight seal joint for each conduit in thesection 488 with the corresponding bore 484. This connection is made bya simple axial movement bringing the parts together and is independentof reasonable variations in th distance at which the sleeves 488 areinserted in the bores 488 and 488. Since the sleeves are supportedagainst expansive forces only at the beaded ends, it will be seen thatas the pressure rises, the sleeve tends to assume a barrel shape. thusmoretightly sealing with the walls of the bore.

The shaft 888 carries the coupling member 828 which is engageablewith'the tongue-828 by a straight axial-movement; thus the housingsection 58 may be assembled to the housing section 58 by merely securingthe bolts. not shown, which hold the flange portion against the flange88 of the housing 58. In so doing, a driving connection is establishedat the coupling 828 and the group of conduits 488 are individuallyconnected to the corresponding bores 484,

At their righthand ends, the tubes 488 are provided with integral beadedportions 888 engageable in bores 882 formed in the response pump securedby welding to a manifold block 588 in and opening to the adjacent faceof the casing member 88. A connection block 482 is secured to the plateI88 on the opposite side from the motor and control valve block I88 andhas a plurality of bores 484 forming continuations of the conduitsembraced in the tubes 488'. The end of the block 482 adjacent'the block488 is provided with counterbores 488 similar to the bores are aplurality of coupling sleeves 488 which are provided with beaded endswhich are a slight the upper part of the housing 88.

Referring to Figure 8, the conduits continue in the vertical casingsection 84 through a block 888, coupling sleeves 8I8 being provided toconnect the block 888 to the block 588. The shaft 342 being splined inthe hub 858, the upper section 84 may be assembled to the housingsection 58 by an axial movement, the securing of the bolts at the flangeconnection serving to establish the conduit and shaft connections inaddition to securing the two housing portions together.

The control head housing is provided with a conduit block 5I2 (Figure12) having bores 5I4 engageable with the beaded upper ends of theconduit tubes 5I8 which are welded in the upper end of block 588. Thebearing cup-818 -being slidable in the housing 88 and the bevel gear 818being no greater in diameter than the bearing 818, the head 88 may beassembled onto the top of the vertical casing 84 in the same manner asthe other casings are assembled together.

In operation, using the prime mover I8 as a source of power and the handwheels 38 as-the primary controlling-elements with the motor I 8 inoperation, oil will be delivered by the auxiliary pump 82 into theconduit 48I, and pressure will build up therein to the value at whichthe relief valve 448 opens. This pressure is more than sumcient toovercome the spring bias of the lookout plunger pistons 288 and projectthe same inwardly to block the torque responsive anti-kick valve 48 incentral position. Should any replenishing fluid be required in thecontrol circuit 88-82 or in the main circuit I4I8, the correspondingreplenishing valves 454-488-488-488 will open until the pressure in eachof these conduits equals the pressure in conduit 48I.

As the relief valve 448 moves to the left, it cuts on the clutchcylinder 428 from the tank connection 488 and opens it to the conduit I,thus admitting fluid to advance the plunger 428. 'The clutch shifterlever 482 accordingly moves to the right in Figure 1 disengaging thehand wheel shaft from the pinion 888. The bypass valve auasos 13 I isalso moved to therllhhcloslngthem around the primary control pump 84.The'circult is thus automatically placed in condition for wheels 88 areturnedin one direction, say, top.

toward observer, the control pump 84 will deliver fluid into one of theconduits, 88 for example, and

since the response pump 88 is maintained stationary for the moment byits connection to the load device 28, this fluid will be delivered tothe right end of the control motor 28, thus throwing the pump yoke 18 onstroke to the right to cause delivery of fluid through line I8 to themotor I8 and consequent rotation of the load device 28 in the desiredcounterclockwise direction. Checkvalve I88 permits this flow to passfreely from line I8 to port I18 and, as soon as pressure builds up inlines I8 and I88, valve 48 will shift to the right. opening the returnpath from the motor I8 through line I8 and port 288, which path waspreviously blocked by check valve I18. The lockout plungers238 beingheld in by pressure from pump 82 through line "I, the valve 48 remainsin its central position permitting free flow through conduits I8 and I8in.either direction. As soon as this rotation starts, the pump 88 isturned correspondingly and acts W withdraw fluid from the conduit 88into which the pump 38 is pumping fluid. Thus the motor 28 remainsstationary so long as the handwheels continue to be turned at thesamerate of speed because the same quantity of oil is withdrawn by pump38 out of conduit 88 as pump 88 delivers into it (both the hand wheels88 and the output shaft 28 being driven at corresponding speeds). Forthis purpose the volumetric capacities of pumps 38 and 88 and the ratiosof their drive gearing are properly selected to produce equal'fluiddisplacements per unit of time when the hand whee s and output shaftsturn at corresponding speeds (that is, gear 888 (Figure turns at thesame speed and direction as gear 888). -As soon as they are stopped, thecontinued rotation of the load device drives the response pump 88delivering fluid to the left end of the motor 28 and returning the yoke18 to neutral position. When this position is reached, the response pumpstops turning due to stoppage of the load device 28. The elementsconnected to the conduits 88 and 32 thus comprise a follow-up controlsystem in which the stroke of the pump I2 is made dependent upon thedifference in angular position between the hand wheels 88 and the loaddevice 28.

Should the hand wheels 38tend to depart from synchronized position withthe load device 28. that is, beyond the amount necessary to operate thestroke regulating motor 28, due to leakage from any part of the circuit38-32 or to other causes; the synchronizing valve 83 will be 80811? atedby the differential mechanism at sleeve 888.

When this error exceeds a certain limit'determined by the gear andleverage ratios of the mechanism. valve 5 shifts to the left or right asrequired and after a predetermined movement as determined by the overlapin the valve opens one of the ports 1 to one of the ports 9. Fluid fromthe auxiliary pump 82 is thus admitted to whichever of the controlconduits 38 or 32 requires more oil in order to bring about synchronism.At the-same time'th'e other port 1 is opened to the interior-ofthecasing thus exhausting oil from the other. control line. Thissynchronizing action terminates as soon as the load device 28 has. beenmoved sumciently to bring the valve 8 backtoclosed position. In:

this connection the term "synchronize" and its derivatives is usedherein and in the claims to indicate such action as will cause theposition of the load device to correspond to the position of the handwheels as if they were mechanically connected irrespective of whetherthe speed ratio of such connection beone to one or some other ratio.

During operation in thismanner, the motor I8 is'constantly protectedagainst overload by the constant horsepower valves I88 and III which actin the manner previously described to prevent'the product of pressure inthe lines I8 or I8 and stroke of the pump I2 froinexceeding apredetermined value which will not overload the prime mover l8. Thus asteady resistance at the load device 28 which-is too great to beovercome at full speed will be overcome at the greatest lower speedwhich the horsepower capacity of the motor I8 will permit; Duringoperation under such overload conditions, the conduits and 82 arebypassed through one of the valves in the block 48, thus permitting theoperator to continue to turn the hand wheels 88 without adverse effectOn the mechanism. I

Should a sudden resistance be encountered at the load device 28tendingto move the same, for example, clockwise, in opposition to its intendeddirection of movement while the yoke II is on stroke to the right, thecheck valve I88 will prevent back flow to the pump I2 through line I8,while if the sudden applied resistance is suiflcient to'actually slowdown themotor I8 or turn it backwardly, the corresponding relief valve812 will limit the pressure in the motor side of the circuit to a safevalue not injurious to the motor I8. It will be noted that whenever anysignificant resisting pressureexists in one of the main circuit conduitsI8. for example, the anti-kick valve 88 moves to the right. During suchsudden resisting overloads, the valve remains in its shifted position,and the check valve I88 acts to prevent back flow in the pressure linein the event the pump relief valve 888 should open. Should the loaddevice 28 be subjected toa sudden external counterclockwise forcecausing the same to overrun its normal drive by the motor l8, the

first thing that happens is that the pressure in the main circuit flrstbecomes equalized and then reverses, that is, it shifts to the line Itin which fluid is returning from the motor to the pump. Thisequalization of pressure causes the valve 88 to return to centralposition in which the returnv line I8 is blocked, so that it isimpossible for the motor I8 to overrun the pump I2 except by developingsufficient pressure to open the relief valve 818.

During normal operation intermediate the limiting positions of the loaddevice 28, the limit stop valves 88 and 52 permit free flow around theircheck valves 288 and 284 in either direction.

when one of thelimiting positions is reached, say.

a 15 these conditions, the line l4- which was the return line nowbecomes the pressure line, and the fluid is permitted to flow in thisline to the motor through the check valve 284 at the closed limit stopvalve 52.

Should the prime mover l become disabled for any reason and it becomenecessary to operate the loaddevice by hand,. the pump "being no longerdriven, fluid is permitted to exhaust from behind the lockout plungers238 by leakage, and the valve 440 moves to the right for the samereason. Movement of the latter quickly exhausts available forreplenishing the main circuit lines.

' For this.reason,'the auxiliary reservoir 419 in the vertical housing'4 forms a supply of replenishing'fluid which is admitted as needed theclutch control cylinder 426, thus retracting the plunger 420, andpermitting the shifter fork 442 to move to the left to the position ofFigure l. The bypass valve 4 again opens and the hand wheels are now'clutched to the pinion 388 which through the gearing and shaftconnections previously described connect directly to the load. device26. Preferably the gear ratio between the hand wheels 38 and the loaddevice 28 under these conditionsis considerably lower than that duringpower operation. as shown more par-.

ticulariy in Figure 10.

Due to the lockout plungers 230 having been retracted, the torqueresponsive valve 48 is now free to operate and shifts to the right orleft when torque is applied to the hand wheels in one direction or theother. During normal operation, say, with hand wheels 38 being turnedtop toward observer, the movement of the valve 48 is to the left andopensthe bypass through conduit 234 and check valve 236 so that themotor It may be turned idly pumping oil into lines l4 and 234 againstthe negligible resistance of the check valve 236 from which it returnsthrough line It to the motor l8.

should the resisting load become too great and tend to drive the motor I8 reversely, the check valve 236 prevents such flow. The torque limitingclutch 368-410 limits the torque which may be applied by the hand wheels38, while the check valve 236 acts as a sort of hydraulic ratchetpreventing back rotation of the motor l8.

Valve 48 also acts to prevent over running of the motor it due to anexternal force applied to the load device in its intended direction ofmovement. As soon as such overrunning force, say. tending to drive theload counterclockwise, moves the load device slightly ahead of thecorresponding position of the hand wheels 3!, the torque responsivemechanism at the valve 48 permits the latter to center, thus blockingthe bypass through the check valve 236. With the valve 48 thus centered,the check valve I18 prevents flow of oil out of the motor I! except at apressure high enough to open the motor relief valve 410. Should theoverrunning force be applied sufliciently to cause the load 26 to getmaterially ahead of hand wheels 38, the torque responsive mechanismcauses the valve 48 to shift beyond center to the right, thus connectingconduit l4, which is still the return conduit from the motor, to theupper of the valve 48.

through the conduit 418 and the proper check valve 414 or 416.

Provision is also made for preventing leakage of oil or entrance of airfrom the parts in the 7 projecting stems of the limit stop valves- 50and 52 are sealed by the grooves 256 and "258 and connecting channels 2"and 262. Thus a sup'-;

ply of oil is maintained for :sealing the working-' parts of the,circuit which are utilized during The auxiliary. reservoir is main-;

tained filled during power operation by the over.-

direct drive.

flow from the relief valve 440, thus insuring that at any time when itis necessary to go over to direct manual drive, there will be an amplesup- I ply of oil in the reservoir!" even though the,

main reservoir be emptied during hand.operation. This overflow of oil n'om.the- 'reliefvalve- 440 also passes down over theun'echa'fiisihjn theupright housing section, providing lubrication of the working partsthereof.

The operation of the auxiliary --reservoir-sys-. tem may be traced indetail as follows: With the main reservoir to the'left of plate 198 inFigure 7 filled with a substantial quantity of n "and with the motor I!in operation; th'e fpump 82 de'-" livers auxiliary pressure-oil tothe'various coritrol and replenishing circuits as previously described.Thejexoess -oil'. not used in these circuits is passed over the'relie'fvalve 440 and enters the interior pf-tlie casing 88 through pipe 43!.This overflow falls by gravity over the mechanism within casing 66furnishing lubrication thereto and collects at the bottom of easing '6.From there it passes by gravity through hole In (Figure 12) and dropsonto the brake mechanism 312. This flow path is side of the check valve236, which then acts to-- figure. Most of this 011 ands its'iway downpast the brake mechanism and through bearings 358 (Figure 8) into therighthand-portion of casing 64 which is the auxiliary reservoir 419. 4This oil collects in theauxiliary reservoir, since auxiliary pumppressure is holding one ofjthe check valves 414-418 closed and main pumppressure is holding the other closed and there can accordingly 4 .be no'drainage of this oil out of conduit 418. -The auxiliaryreservoir isfilled in this manner soon after the motor II is first placed inoperation and thereafter overflows into the tube 524. This overflowtakes place over the top edge of the-

